A report in Cell today (October 3) now provides such evidence, at least for one endosymbiont, the bacterium Moranella, and its host, the mealybug Planococcus citri. The study shows that the two work ...

The captured cell (the endosymbiont) was then reduced to a functional organelle bound by two membranes, and was transmitted vertically to subsequent generations. This unlikely set of events ...